Network problem

[Chris Brenton]

I'm assuming Tom forgot to re-all on his note again so I've cc'd the group.

Tom Fogal wrote:
> 
> Now that I look it up, it is not as specific as either of us thought. In 802.3
> it is simply defined (in clause 1.4.81) as 'A condition that results from
> concurrent transmissions from multiple data terminal equipment sources within
> a single collision domain.' It doesnt mention frames or differences on transmit/
> receive pairs..

Agreed, but the fact that multiple transmissions are taking place has to 
be _detected_ somehow. The method implemented is to monitor the receive 
pair while transmitting. If the pattern does not match, an error has 
occurred.

> CSMA/CD -may- be followed in full duplex mode, but it is not required.

Humm, the whole point of full duplex mode is that you can transmit while 
receiving. All this really means is that its OK for the bit pattern on 
the transmit and receive pair not to match. It is assumed that only two 
layer two or higher system will occupy any given physical medium, thus 
collision can not occur. Thus full duplex follows CSMA, but not CD.

Sorry to cut this short but I've got to bail,
C